Domestic hot water generator



Nov. 11, 1969 J. L. CURREN DOMESTIC HOT WATER GENERATOR 3 Sheets-Sheet 1 Filed Nov. 14, 196'? INVENTOR. JOHN LEO CURREN Nov. 11, 1969 J. L. CURREN 3,477,503

' DOMESTIC HOT WATER"GENERATOR Filed Nov. 14, 1967 3 Sheets-Sheet 2 FEG. 2

- INVENTOR. JOHN LEO CURREN Nov. 11, 1969 J. L. CURREN 3,477,503

DOMESTIC HOT WATER GENERATOR Filed Nov. 14. 1967 3 Sheets-Sheet 5 FIG. 3

INVENTOR.

JOHN LEO CURREN United States Patent ABSTRACT OF THE DISCLOSURE A heat exchangerparticularly adapted for use as a hotwatergenerator for domestic hot water is described. This hot water generator consists essentially of a vertical tube with ports at top and bottom and an outer tubular jacket having two upper and two lower ports suitab y spaced to permit connecting two or more of the generators in parallel alignment. In operation the inner tube(s) of the generator, or generators, is connected to the hot water.

storage tank and the outer tube(s) is connected to the hot water boiler, e.g., the boiler in the domestic furnace.

Brief summary of invention Most ldomestic hot water systems have the dual funct i on of heating the home by providing hot water to suitably placed radiators or connectors, and of heating water for domestic uses. The hot water for the radiators is heateddirectly in the heating boiler, and is circulated to the radiators by a temperature controlledcirculating pump. The domestic hot water, on the other hand, is usually heated in a separate coil which is immersed in the hot water in the heating boiler, said coil being connected to the domestic hot water service line for distribution to the hot water outlets. p

A definite and recognized limitation of this form of hot water system is its inability to furnish an adequate supply of hot water when the circulating pump becomes activated, thereby returning cold water. from the radiators to the boiler. This flow of cold water to the boiler necessarily cools the domestic hot water coil immersed in the boiler water with the result that cold water is drawn from the hot .water outlets, at least during the early stage of the circulating cycle Some measure of success has been achieved in overcoming this difficulty with the use of a hot water generator exterior to the boiler but the generators used have been bulky and structurally diflicult to service and repair.

An object of this invention is to overcome the abovementioned limitations in hot water systems. Another object is to provide a simple and eflicient hot water system wherein the domestic hot water is heated externally to the boiler. A furtherobject is to provide a novel hot water generator of simple design and of long life expectancy that can be used advantageously in a hot water system. Still another object is to provide a hot water generator that can be used singly, or in multiples, and that can be readily assembled.

- These objects are accomplished by or through the use of a hot water generator consisting essentially of (a) a vertically disposed outer tube having two ports near each i end, the ports at each end being spaced 180 apart (i.e.,

pointing in opposite directions) and the upper and lower ports being concentrically parallel to each other, and (b) an inner tube extending through and beyond the ends of .said outer tube, the top and bottom of the outer tube being hermetically sealed around the inner tube. In use, the outer tube of the generator is connected to the hot water boiler and the inner tube is connected to the hot water storage tank.

The four ports in the outer tube of the hot water generator of this invention permit the generator(s) to be coupled in parallel to increase capacity if desired. When a single generator is used in a hot water system, one of the upper ports and one of the lower ports in the outer tube are capped, the remaining ports in the outer tube being connected to thegflhot water boiler. When two or more generators are used, they are positioned in parallel with adjacent upper ports in the outer tubes connected to each other and the adjacent lower ports of the oute tubes joined together, leaving one upper and one lower port on each of the outermost generators, In operation, the remaining upper port on one of the outermost generators and the remaining lower port on the other outer most generators are connected to the hot water boiler, the remaining upper and lower ports .being capped. The upper ends of the inner tubes of the generators used in parallel are connected to a common header, which in turn is connected to or near the top of the hot water storage tank, and the lower ends of the inner tubes of the generators are connected toa common header which is connected to or near the bottom of the storage tank.

Brief description of drawings FIGURE 1 is an open vertical sectional view of the hot water generator that constitutes the novel features of this invention. I v

FIGURE 2 is a vertical view of two generators assembled in series and showing method of assembly when generators are for multiple usage.

FIGURE 3 is a schematic view in front elevation of a domestic hot water system having two generators in parallel and showing the connection of this double generator to a hot water heating boiler and a hot water storage tank.

The drawings show the directional flow of water through the generators.

Detailed description and 7, which are sealed iinto the outer tube byinternallj welded, flared and locked joints 8 thereby forming a generator of unit construction as shown in FIGURE ,1"; The directional flow of water'in the generator while: in use is shown by arrows 9-9 and 10-10'. i I FIGURE 2 is an external vertical view shown entering at bottoms of generators as.. 1 1-, and this water flow from the tops. of "generators back intol upper circulating tapping he storage tank is shown 'as l i"; Convectional water flow from the upper, circulating (tap;

ping in the heating boiler enteriug 'the upperfjacketinlet port is shown as 12, and this water flow from the lower jacket outlet port back to the lower inlet in theboiler is shown as 12'. The upper boilertapping must be on. the boiler side of the flow valve, and the lower boiler tapping must be on the boiler side of the circulating pump.

These two countercurrent bodies of water,.the inner body being of city water pressure and the'jacketed body of water being of heating boiler pressure, are. never dormant. This physical phenomenon is due to the ever changing gravity differential in any gravity convectional circulating body of water, as control ed by the acquisition of, or release of, contained heat therein. Shown as 13. are caps to seal unused outlets in jacket, and also shown as14 are connecting couplings used in two or more generator assemblies.

. iled hoiwater generators in parallel. Convectional water fiow from the lower circulating tapping of the storage tank is,

FIGURE 3 shows schematically the hook up from the hot water heating boiler 16 to the double generator 21 and from this generator to the hot water storage tank described above. Hot water from the hot water boiler 16 enters the jacketed areas, i.e., the outer tubes, of the generator, through circulating line 12. This water body, after its downward flow, through the jacketed areas of the generator, exits through circulating line 12' and reenters the hot water boiler at a tapping near the bottom of the boiler. Hot water storage tank 15 is connected to the inner tubes of the generator by circulating lines 11 and 11'. The lower circulating line 11 conveys Water from the storage tank to the lower ends of the inner tubes of the generator. As this body of water enters the inner tubes it rises to the top of the inner tubes and flows back to the hot water storage tank through circulating line 11'. The physical behavior of the two bodies of Water passing through the generator, i.e., the body flowing through the outer tubes and the body flowing through the inner tubes of the generator, has been described in connection with FIGURE 2. The hot water storage tank shows cold water flowing into the tank as 20, and hot water flowing from the tank as 19 for all domestic uses.

FIGURE 3 also indicates the manner in which boiler 16 provides hot Water for home heating. This body of water passes through flow valve 18 to the areas to be heated, and the return of this water to the boiler through circulating pump 17. This home heating circuit has no adverse effect on the generation of domestic hot water during any seasonal cycle of the home heating system.

The hot water generator of this invention can be constructed from conventional tubing or piping, copper tubing being particularly adaptable. For highest efficiencies, the cross-sectional areas of the inner and outer tubes of the generator should be as nearly equal to each other as conventional piping or tubing sizes will permit. Performance tests show it is advantageous to have the circulating lines to and from the storage tank the full size as the tappings in the storage tank, since this greatly improves the recovery factor of the domestic hot water system.

The overall size or capacity of the generator or generators varies with specific demands of the installation, by single generator use or by multiple use as a ready described. This generator is highly efiicient, and as a replacement for an immersed coil installation, has proven very satisfactory supplying hot water for a large family of seven with three baths and a constantly used home laundry. In this replacement installation two small generators in parallel are used, in conjunction with a 40-gallon hot water storage tank.

The hot water generator of this invention has the following desirable features and advantages. As already described, it is highly efficient. It is also sturdy and can, for example, be installed in a domestic hot water system as depicted in FIGURE 3 without the use of a hanger or loose support. A further important advantage is the absence of any covered joint or point of assembly on either the inner tube, which carries city water pressure in normal use, or the outer tube or jacket, which carries reduced pressure of the heating system (boiler water). This facilitates installation and possible repair. A further advantage of this domestic hot water system, as already described, is that operation of the circulating pump has no influence on the flow of hot water to and from the hot water storage tank, or the convectional flow of hot water from the heating boiler to and from the hot water generator or generators. To applicants knowledge, no other hot water generator has these many advantages, at least not to an equal degree.

Although the hot water generator of this inventionhas been described with particular reference to its use in conjunction with a hot water heating boiler and storage tank to furnish domestic hot water, it will be apparent to those skilled in the art that the generator can be used in other applications requiring an efllcient hot water generator, or more broadly a heat exchanger for liquid media. It will also be apparent that the metals of construction can vary to suit specific applications.

Having now described the invention in specific detail, and exemplified the manner in which it may be carried into practice, it will be readily apparent to those skilled in the art that innumerable variations, modifications, applications, and extensions of the basic principles involved may be made without departing from its spirit and scope.

What is claimed is:

1. A hot Water generator comprising:

(a) an outer tube having near each end two ports each consisting of an open end outwardly-protruding tubular member sealed into the outer tube, the ports at each end being spaced 180 apart, and the ports at one end being concentrically parallel to those at the other end; and

(b) an inner tube extending through and beyond the ends of said outer tube, the ends of the outer tube being hermetically sealed around the inner tube by means of drive-fit metal plugs made of the same metal as the tubes and welded in position.

References Cited UNITED STATES PATENTS 788,089 4/1905 Blackmore 122-32 1,108,463 8/1914 Moore 122-32 1,791,531 2/1931 Morrow 122-32 X 923,025 5/1909 Curran -154 1,206,789 12/1916 Adams 122-32 1,377,714 5/1921 Manning et a1. 126-362 1,401,523 12/1921 Coates 237-19 1,774,041 8/1930 Stack 165-139 2,155,666 4/1939 Leidig 165-154 X 2,204,708 6/1940 Smith 237-19 X 3,151,672 10/1964 Edmund 165-143 FOREIGN PATENTS 960,010 6/ 1964 Great Britain.

ROBERT A. OLEARY, Primary Examiner ALBERT W. DAVIS, Assistant Examiner US. Cl. X.R. 

